Buff Roo x Chocolate Hen

[MyBabiesTheChickens]

Hi! I've seen that a Chocolate Roo over Buff hen creat sex linked Chocolate hens and black roos. How does this apply for Silkies with a Buff roo over Chocolate hen? I bred a white roo to the chocolate hen and got a black hen, so that was a bit odd as well since I learned that Chocolate is a sex linked color and only needs one copy for hens to appear Chocolate. Thanks in advanced for any answers.

 

[sylviethecochin]

Okay. Sexlinking works thusly:

With animals, chromosomes come in pairs. This is relevant, because chromosomes are made of genes. The members of the pairs are a reflection of each other, and carry the same genes in the same places.

For illustration's sake: (pretend each letter represents a gene)

chromosome 1: g h y t j k i r s l p o m
chromosome 2: g h y t j k i r s l p o m

Sometimes, the genes are differ slightly from their original form. Those slight differentiations are called alleles--basically a variation on the same gene. Those variations can be dominant or recessive to the original gene. For instance, chocolate is a dominant variation of black.

Now throw some alleles in there:

chromosome 1: g H y t j k I r s l P o m
chromosome 2: g h y T j k i R s l p O m

Capitals represent dominant genes, so the bird's appearance (just pretend these are all color genes) would be g H y T j k I R s l P O m

But there is one different pair of chromosomes. These are the sex chromosomes. And one of the sex chromosomes is shorter than the other. The rooster carries two long chromosomes, and the hen carries a long and a short chromosome. Because that chromosome is shorter, it's missing some genes.

Rooster: g H y t j k I r s l p o m
g h y T j k i R s l p o m

Hen: g H y t j k I r s l p O M
g h y T j k i R s l p + +

The hen and the rooster each give their baby a randomised set of genes, but the genes will be inherited on chromosomes. The hen will give half her babies a short chromosome--an incomplete one. A chromosome that's missing genes (Oh, NO!) But it's alright--those defective chicks are just the next generation of females. And those missing genes are the sexlinked ones.

The rooster chicks will inherit a long chromosome from Mum.

Now these hen chicks don't just have the short chromosome that's missing genes. They also have a set from Dad. And because they only have one copy of those sexlinked genes, they're forced to express them.

Now if you check that string of "genes" for the hen and rooster above, you'll see that my imaginary sexlinked genes are O and M. Dad only has the recessive alleles(o m) and mum only has dominant alleles (O M)

The rooster chicks inherit the long chromosome from Mum. They get her dominant genes, and a set of recessive ones from Dad. They express the dominant ones. You get a black (or barred, or silver, or whatever dominant sexlinked gene you used) rooster.

The hen chicks inherit the short chromosome. They get her lack of genes, and the set of recessive ones from Dad. They only have one set to express, so they show the recessive genes. You get chocolate hens.

Switch that around. Give Dad the dominant genes, and Mum the recessive ones.

Dad can only pass on O and M.
Mum can only pass on o and m.

So the hen has a missing set of genes for her female chicks, which will show Dad's genes, since they're the only ones that they have. The rooster chicks will have one copy of Mum's recessive genes, and one copy of Dad's dominant genes. They too will show the dominant genes. The chicks will not be sexlinked.

TLDR: it only works if the hen is the one carrying dominant genes, and the rooster carries recessive.

 

[Sally PB]

 

[MyBabiesTheChickens]

Okay. Sexlinking works thusly:

With animals, chromosomes come in pairs. This is relevant, because chromosomes are made of genes. The members of the pairs are a reflection of each other, and carry the same genes in the same places.

For illustration's sake: (pretend each letter represents a gene)

chromosome 1: g h y t j k i r s l p o m
chromosome 2: g h y t j k i r s l p o m

Sometimes, the genes are differ slightly from their original form. Those slight differentiations are called alleles--basically a variation on the same gene. Those variations can be dominant or recessive to the original gene. For instance, chocolate is a dominant variation of black.

Now throw some alleles in there:

chromosome 1: g H y t j k I r s l P o m
chromosome 2: g h y T j k i R s l p O m

Capitals represent dominant genes, so the bird's appearance (just pretend these are all color genes) would be g H y T j k I R s l P O m

But there is one different pair of chromosomes. These are the sex chromosomes. And one of the sex chromosomes is shorter than the other. The rooster carries two long chromosomes, and the hen carries a long and a short chromosome. Because that chromosome is shorter, it's missing some genes.

Rooster: g H y t j k I r s l p o m
g h y T j k i R s l p o m

Hen: g H y t j k I r s l p O M
g h y T j k i R s l p + +

The hen and the rooster each give their baby a randomised set of genes, but the genes will be inherited on chromosomes. The hen will give half her babies a short chromosome--an incomplete one. A chromosome that's missing genes (Oh, NO!) But it's alright--those defective chicks are just the next generation of females. And those missing genes are the sexlinked ones.

The rooster chicks will inherit a long chromosome from Mum.

Now these hen chicks don't just have the short chromosome that's missing genes. They also have a set from Dad. And because they only have one copy of those sexlinked genes, they're forced to express them.

Now if you check that string of "genes" for the hen and rooster above, you'll see that my imaginary sexlinked genes are O and M. Dad only has the recessive alleles(o m) and mum only has dominant alleles (O M)

The rooster chicks inherit the long chromosome from Mum. They get her dominant genes, and a set of recessive ones from Dad. They express the dominant ones. You get a black (or barred, or silver, or whatever dominant sexlinked gene you used) rooster.

The hen chicks inherit the short chromosome. They get her lack of genes, and the set of recessive ones from Dad. They only have one set to express, so they show the recessive genes. You get chocolate hens.

Switch that around. Give Dad the dominant genes, and Mum the recessive ones.

Dad can only pass on O and M.
Mum can only pass on o and m.

So the hen has a missing set of genes for her female chicks, which will show Dad's genes, since they're the only ones that they have. The rooster chicks will have one copy of Mum's recessive genes, and one copy of Dad's dominant genes. They too will show the dominant genes. The chicks will not be sexlinked.

TLDR: it only works if the hen is the one carrying dominant genes, and the rooster carries recessive.

So could I still get chocolate chicks with the silver/gold leakage?

 

[pipdzipdnreadytogo]

Chocolate is actually sexlinked recessive, so it works a bit differently than the sexlinked dominant genes like barring and silver.

The long and short chromosome stuff is correct. Males have a pair of matching long sex chromosomes, ZZ, while females have a mismatched set of one long and one short sex chromosome, ZW. This means that the male always passes on a Z chromosome to his offspring and it is the female who is the one who determines the sex of the offspring; she either passes on a Z or a W chromosome, pairing with the male's Z chromosome to make either ZZ or ZW.

Sexlinked genes exist on the long sex chromosome, Z, but not on the short one, W. They function as sexlinked because the hen only ever sends that Z chromosome to her sons, never her daughters. In that way, you can manipulate the appearance of the chicks by selectively pairing her with a male of the appropriate genes.

Now, with sexlinked dominant genes, you want the hen to have the sexlinked gene and the rooster to not have the sexlinked gene. This is because she will only send that dominant sexlinked gene to her sons, and so her daughters will not inherit it because their father does not also have the gene. The gene expresses because it is dominant.

With sexlinked recessive, it's the opposite. Sexlinked recessive genes can only express if there is not a more dominant gene present. Hens only need one copy of a sexlinked recessive gene to express it because it only exists on the Z chromosome, so the W chromosome will never have the dominant gene to cover it up. However, males must have two copies of the gene to express it, one on both Z chromosomes.

OP, you have a Chocolate female; that means she has a recessive Chocolate gene on her Z chromosome that she will only ever pass on to her sons. The male she has mated with has two dominant non-chocolate genes on his Z chromosomes that he gives to all of his offspring. Thus, the expected result from that crossing would be non-chocolate offspring, but all of the male offspring from this pairing will carry one copy of chocolate without expressing it. You cannot get Chocolate from a Chocolate hen unless the male she is paired with is also Chocolate or at least carries one copy of the Chocolate gene.

Creating sexlinks works with a Chocolate male and non-Chocolate female because he gives all of his offspring a Z chromosome with the chocolate gene, while the hen he is paired with only ever gives her sons the more dominant non-chocolate gene. That covers up chocolate in the sons, but since chocolate is not on the W chromosome she gives to her daughters, there is nothing to cover up the father's chocolate gene from his Z chromosome. Thus, you get non-chocolate males and chocolate females from that cross.



Editing, and I just noticed the edits to that other post. Serves me right for reading it in the middle of the night and then not rereading to respond this morning.

 

[MyBabiesTheChickens]

Chocolate is actually sexlinked recessive, so it works a bit differently than the sexlinked dominant genes like barring and silver.

The long and short chromosome stuff is correct. Males have a pair of matching long sex chromosomes, ZZ, while females have a mismatched set of one long and one short sex chromosome, ZW. This means that the male always passes on a Z chromosome to his offspring and it is the female who is the one who determines the sex of the offspring; she either passes on a Z or a W chromosome, pairing with the male's Z chromosome to make either ZZ or ZW.

Sexlinked genes exist on the long sex chromosome, Z, but not on the short one, W. They function as sexlinked because the hen only ever sends that Z chromosome to her sons, never her daughters. In that way, you can manipulate the appearance of the chicks by selectively pairing her with a male of the appropriate genes.

Now, with sexlinked dominant genes, you want the hen to have the sexlinked gene and the rooster to not have the sexlinked gene. This is because she will only send that dominant sexlinked gene to her sons, and so her daughters will not inherit it because their father does not also have the gene. The gene expresses because it is dominant.

With sexlinked recessive, it's the opposite. Sexlinked recessive genes can only express if there is not a more dominant gene present. Hens only need one copy of a sexlinked recessive gene to express it because it only exists on the Z chromosome, so the W chromosome will never have the dominant gene to cover it up. However, males must have two copies of the gene to express it, one on both Z chromosomes.

OP, you have a Chocolate female; that means she has a recessive Chocolate gene on her Z chromosome that she will only ever pass on to her sons. The male she has mated with has two dominant non-chocolate genes on his Z chromosomes that he gives to all of his offspring. Thus, the expected result from that crossing would be non-chocolate offspring, but all of the male offspring from this pairing will carry one copy of chocolate without expressing it. You cannot get Chocolate from a Chocolate hen unless the male she is paired with is also Chocolate or at least carries one copy of the Chocolate gene.

Creating sexlinks works with a Chocolate male and non-Chocolate female because he gives all of his offspring a Z chromosome with the chocolate gene, while the hen he is paired with only ever gives her sons the more dominant non-chocolate gene. That covers up chocolate in the sons, but since chocolate is not on the W chromosome she gives to her daughters, there is nothing to cover up the father's chocolate gene from his Z chromosome. Thus, you get non-chocolate males and chocolate females from that cross.



Editing, and I just noticed the edits to that other post. Serves me right for reading it in the middle of the night and then not rereading to respond this morning.

Bummer. So I won't get chocolate chicks, but will I get those cute leakages? Hoping at least for some leakages in those black chicks I'll be getting.

 

[pipdzipdnreadytogo]

Yes, from that crossing, you should expect mostly black chicks who develop varying amounts of reddish or gold leakage as they feather in.

 

[MyBabiesTheChickens]

Yes, from that crossing, you should expect mostly black chicks who develop varying amounts of reddish or gold leakage as they feather in.

Thank you! I guess I will have to be satisfied with that. XD

 

[sylviethecochin]

Editing, and I just noticed the edits to that other post. Serves me right for reading it in the middle of the night and then not rereading to respond this morning.

Ninja.

I am impressed you caught it in the what, ten minutes between my posting and editing? (and now, to edit this post, I will say it wasn't the only mistake. I had to edit that baby a couple times.)

 

[MyBabiesTheChickens]

Ninja.

I am impressed you caught it in the what, ten minutes between my posting and editing? (and now, to edit this post, I will say it wasn't the only mistake. I had to edit that baby a couple times.)

Lol! I just really only have all you experienced breeders for answers, so I like to keep up with what's going on. I am also getting Gmail notifications for replies.